#include <stdio.h>
int main(void){
	int n,m,i,j,k,t,result;
	printf("plz enter n&m\n");
	scanf("%d%d",&n,&m);
	j=1;
	k=1;
	for(i=m;i>=1;i--){
		j=j*i;
	}
	for(t=1;t<=m-n;t++){
		k=t*k;
	}
	result = j/k;
	printf("%d",result);
	return 0;
}
